Polymers can be colored with dyes in various ways. One way is mass coloration of polymers whereby for example a pigment or a dye is mixed with the polymer and the polymer is melted to transport the dye into the polymer matrix. Other processes involve the polymer being colored, or to be more precise dyed, by the dyes diffusing into the polymer from a solution or dispersion, examples being the dyeing of polymeric fibers composed of polyester, polyacrylonitrile, polyurethane, cellulose or polyamide for example with, for example, disperse dyes, cationic dyes, acid dyes, metallized dyes or reactive dyes. The use of reactive dyes results in a covalent bond being performed between the dye and the substrate, conferring particularly high fastnesses on the dyeings/colorations. Another way to color a polymer is to add the dye to the polymer's monomers or oligomers, before the polymer is formed or as it is being formed. Dyes capable of forming covalent bonds with the polymer scaffold may likewise result in colorations of high fastness being obtained. For this, the dyes used, or to be more precise their chromophores, have to be sufficiently stable under the conditions of the polymerization.
Commercially available pigments when used in mass coloration of polymers do give colored polymers of predominantly high fastnesses, but the colorations are dull, i.e., lack transparency. Commercially available dyes for polymers are usually disperse dyes or solvent dyes and produce, when used for the coloration of polymers, colored polymers in which the dye often only has low bleed fastnesses. In addition, many of the known dyes have poor lightfastnesses or low thermal stabilities. In polyolefins, Dyes having good bleed fastnesses, good lightfastnesses, good thermal stabilities as well as high saturation and transparency in polyolefins without adversely affecting the properties of the polyolefins used are not known in large numbers.
EP 0 006 122 A1 discloses perylene dyes which meet the above-recited requirements only in part since they are not suitable when high bleed and wet gap fastnesses are desired.
EP 0 283 436 A2 describes perylenediimides having aliphatic radicals containing carboxy and/or carbamoyl groups attached to both nitrogen atoms. These dyes do give good results in the coloration of polyolefins, but there continues to be a broad need for improvements, for example with regard to the transparency of the colorations or the thermal stability of the colorations.
JP 2006098927, JP 10006645, US2007/0221913A1 and WO2007/099059 A1 and also J. Phys. Chem. B., 3, Jul. 2008, 112, Supporting Information, S1-S13, J. Org. Chem. 2005, 70, 8956-8962 and Chem. Mater. 1998, 10, 3603-3610 also already describe perylene dyes having poly(oxy)alkyl chains, but do not disclose their use for polymer coloration.